Polymer coating protects MXene, boosts carbon dioxide-to-methane output

A research team led by Professor Su-Il In of the Department of Energy Science & Engineering at DGIST (Daegu Gyeongbuk Institute of Science and Technology) developed a photocatalytic technology that improves the stability of MXene, according to Phys.org. MXene is a two-dimensional nanomaterial with excellent electrical conductivity. The team worked with groups led by professor Insik In of Korea National University of Transportation, Professor Taegyeong Lee of Hanyang University and Professor Soorathep Kheawhom of Chulalongkorn University in Thailand.

According to Phys.org, MXene is easily oxidized when exposed to water and oxygen, which degrades its performance. The team applied a surface modification technique that bonds an organic polymer to the MXene surface to form a protective layer. Phys.org reported the coated material maintained stable performance even in environments where water is present.

The team combined the surface-modified MXene (f-MXene) with reduced TiO₂ (RT), which triggers chemical reactions upon exposure to light, and copper (Cu) nanoparticles. A photocatalyst is a material that drives chemical reactions using light. According to Phys.org, the MXene facilitates electron transfer, the movement of electrons, while the copper promotes the reaction that converts carbon dioxide into methane.

Experimental results showed the Cu/f-MXene/RT photocatalyst produced 18.1 μmol/g (micromoles per gram) of methane, about 200 times the performance of RT alone, according to Phys.org. Phys.org reported that experiments and theoretical calculations confirmed how the surface-modified MXene and copper nanoparticles facilitate electron transfer and promote methane formation.

Su-Il In said the study simultaneously improved the photocatalyst's stability and its carbon dioxide conversion performance by controlling the surface of MXene, which he described as vulnerable to water and light. He said the team expects the technology to be used for carbon resource conversion that uses sunlight to convert carbon dioxide into useful fuels such as methane.

The paper, by Dongyun Kim and others, is titled 'Surface-Functionalized MXene for Enhanced Photocatalytic CO₂ Reduction' and was published in Advanced Energy Materials with DOI 10.1002/aenm.71560. Phys.org said its article was provided by the Daegu Gyeongbuk Institute of Science and Technology.